5. Population Distributions & Range

Multiple individuals of the same species in a given area

Population

Important features of a population:
Genetic unit that defines the ___ ____
Has a defined ____ _____
Structure defined by characteristics of the _____, not individual
____ in time due to birth, death, and movement

gene pool
spatial boundary
collective
dynamic

A niche is much like a _____, where no two species will have the exact same niche

fingerprint

Range of abiotic conditions under which a species can persist (where is COULD be found)

Fundamental niche

Range of abiotic and biotic conditions under which a species persists (Where its ACTUALLY found)

Realized niche

If abiotic conditions are suitable, _______ can constrain the fundamental niche into the realized niche

competition

Even if suitable habitat is elsewhere, barriers to _______ can constrain the fundamental niche into a realized niche

dispersal

Outside of competition and barriers to dispersal, _____ can also constrain the fundamental niche into a realized niche

Predation

Modeling that is used to identify the fundamental niche of a species by analyzing the physical conditions of the species current realized niches

Ecological niche modeling

ENMs can be used to predict ______ ____ impacts

climate change

Surveys and abiotic data collection can be used to model how habitat is expected to change under future scenarios, termed ______ ____ models

habitat sustainability models

ENMs can be used to predict _____ ____ by seeing where they currently exist in their native habitat and what foreign areas align with those habitats

species invasions

In order to use an ENM to predict species invasion, you need to know something about their

fundamental and realized niche in their native range

What are the five characteristics of populations distributions?

Geographic range
Abundance
Density
Dispersion
Dispersal

Total area occupied by a population

Geographic range

Number of individuals living within a defined area

Abundance

Number of individuals per unit area or volume

Density

Spacing of individuals relative to one another

Dispersion

Movement of individuals from one area to another

Dispersal

A species that lives in a single, often isolated location

Endemic species

A species that has a very large range that can span multiple continents, may use portions of habitat seasonally

Cosmopolitan species

Are endemic or cosmopolitan species more susceptible to stochastic events/disasters?

Endemic

Dispersion type that is the “null hypothesis”, uncommon in nature

random

Dispersion type that results from limited dispersal, patchy resources, and social behaviors

Clumped/clustered

Dispersion type that is driven by competition 

Uniform/even

Dispersion type can depend on

scale of observation

Dispersal type where individuals move from their birth site to a breeding site

Natal dispersal

Dispersal type where individuals move from one breeding site to another

Breeding dispersal

Migration is _____, dispersal is ______

temporary
permanent

In mammal species, dispersal of juvenile males prevents

inbreeding between relatives

Most individuals disperse a relatively short distance, but ___________ account for rapid colonization of new areas

super-dispersers

The exact distribution of individuals into patches (good patch/poor patch) can be predicted using the ____ _____ ______

ideal free distribution

The ideal free distrribution makes an assumption that there is a ______ _____ between habitat suitability and population density

negative relationship

How many individuals must occupy the high-quality patch before the first individual should move to the low-quality patch?

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